Toroidal plasma source for plasma processing

• US 20020157793A1
• Filed: 06/12/2002
• Published: 10/31/2002
• Est. Priority Date: 05/25/2000
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Loewenhardt, Peter, Parks, John P., Wanamaker, David P., Majewski, Robert B., Lane, Christopher T., Lai, Canfeng, Cox, Michael S., Shamouilian, Shamouil
• Granted Patent: US 6,712,020 B2
• Time in Patent Office: Days
• US Class Current: 156/345.48
• CPC Class Codes: H01J 37/32009 Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources plasma generation in general H05H1/24
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma

Abstract

A toroidal plasma source (28) within a substrate processing chamber (10). The toroidal plasma source forms a poloidal plasma with theta symmetry. The poloidal plasma current is essentially parallel to a surface of the plasma generating structure, thus reducing sputtering erosion of the inner walls. The plasma current is similarly essentially parallel to a process surface (32) of a substrate (34) within the chamber. In a further embodiment, a shaped member (66) between the substrate and the plasma source controls the plasma density in a selected fashion to enhance plasma processing uniformity.

Claims

1. A substrate processing chamber comprising:

a housing that defines a vacuum chamber;

a power supply;

a toroidal plasma source contained within the vacuum chamber, said toroidal plasma source including a core;

a coupling structure configured to transfer energy from said power supply to said toroidal plasma source; and

a substrate support member disposed to hold a substrate within said vacuum chamber such that a process surface of said substrate is opposite and essentially parallel to the core;

wherein said housing comprises a first interior camber surface that separates said toroidal plasma source from said coupling structure; and

wherein an electric field lines generated by said toroidal plasma source are predominantly parallel to said first interior chamber surface.

2. The substrate processing chamber of claim 1 wherein said housing comprises a plurality of interior chamber surfaces including said first surface, a side surface and a top surface;

said substrate support member includes an upper surface that faces said toroidal plasma source; and

said electric field lines are predominantly parallel to said first, side and top surfaces of said housing and said upper surface of said substrate support member.

3. The substrate processing chamber of claim 2 wherein the toroidal plasma source includes a core having a plurality of ferrite segments and a non-magnetic spacer having a selected thickness, the non-magnetic spacer being disposed between two of the plurality of ferrite segments.

4. The substrate processing chamber of claim 2 further comprising an RF generator mounted directly on the chamber and operatively coupled to said core without tunable matching circuitry.

5. The substrate processing chamber of claim 2 further comprising:

a shaped member disposed between the toroidal plasma source and the process surface of the substrate, said shaped member having a bottom surface that is contoured to affect plasma density distribution.

6. The substrate processing chamber of claim 5 wherein the shaped member has an outer perimeter portion extending beyond a substrate edge.

7. A substrate processing chamber comprising:

a housing that defines a vacuum chamber;

a toroidal plasma source contained within the vacuum chamber, said toroidal plasma source including a core;

a toroid cover, having an outer surface that at least partially surrounds said core; and

a substrate support member disposed to hold a substrate within said vacuum chamber such that a process surface of said substrate is opposite and essentially parallel to the core;

wherein electric field lines generated by said toroidal plasma sources are essentially parallel to said outer surface of the toroid cover.

8. The substrate processing chamber of claim 7 further comprising:

a shaped member disposed between the toroidal plasma source and the process surface of the substrate, said shaped member having a bottom surface that is contoured to affect plasma density distribution.

9. The substrate processing chamber of claim 8 wherein the shaped member has an outer perimeter portion extending beyond a substrate edge.

10. A method of forming a plasma in a substrate processing chamber, the method comprising:

providing a plasma precursor gas to the substrate processing chamber;

initiating a plasma in the substrate processing chamber;

applying power to a toroidal plasma source within the substrate processing chamber to form a poloidal plasma, the toroidal plasma source including a primary circuit and a core of a transformer, wherein the poloidal plasma acts as a secondary circuit of the transformer within the processing chamber; and

selectively modifying a density of the poloidal plasma with a shaped member.

11. The method of claim 10 wherein the plasma precursor gas is a deposition precursor gas, the method further comprising a step of depositing a layer on a substrate in the substrate processing chamber.

12. The method of claim 10 wherein the plasma precursor gas is an etching precursor gas, the method further comprising a step of etching a substrate in the substrate processing chamber.

13. The method of claim 10 wherein the plasma precursor gas is a cleaning precursor gas, the method further comprising a step of cleaning the substrate processing chamber.

14. The method of claim 10 wherein the forming a poloidal plasma step forms a poloidal plasma with theta symmetry, the theta symmetry occurring about a center axis of the toroidal plasma source, the center axis being normal to a major plane of the toroidal plasma source.

15. The method of claim 11 wherein the deposition precursor gas is flown into the substrate processing chamber through a gas port disposed on an outer circumference of toroidal plasma source, the gas port extending beyond an edge of a substrate in the substrate processing chamber.